1. Field of the Invention
The present invention relates to a display device with switchable viewing angle and a backlight module thereof. In particular, the present invention relates to a flat display device that carries out the switching of viewing angle electronically by the design of backlight module.
2. Description of the Prior Art
Comparing to traditional cathode ray tube displays (CRT displays), liquid crystal displays (LCDs) have advantages of thinner thickness, lighter weight, lower radiation etc., so that the LCDs take the place of traditional CRT displays and become the mainstream product in the display market as the LCDs are widely employed in all kinds of consumer electronic products.
The display device is one of the indispensable units for electronic devices, especially for notebook computers, personal digital assistants (PDAs), digital cameras, mobile phones, and other portable electronic devices. In order to facilitate the portability, the display devices accordingly shall have properties such as thin, light, and small. Portable electronic devices allow people to make phone calls, send messages and/or emails, edit documents, and perform other life/work activities at anytime and anywhere, so that people are not confined in particular places such as home or office equipped with corresponding electronic devices, increasing the usability and convenience of portable electronic devices in modern life.
However, since portable electronic devices have a high chance of being used in public or open spaces, privacy protection becomes an important issue. For display device, the anti-peeping function is provided to protect privacy. Available anti-peeping products on the market include anti-peeping films, anti-peeping screen protectors, or other anti-peeping devices that are additionally provided on the displays to achieve the anti-peeping effect. The anti-peeping films or other similar products are substantially a type of filter, which can minimize the light exit angle from the display screen. The anti-peeping film disposed on the display device can minimize the viewing angle to provide the anti-peeing function, achieving the effect of privacy protection.
However, the anti-peeping film or other anti-peeping devices is additionally disposed on the screen manually. When not in use, the user also has to remove the anti-peeping film manually. When the attachment and detachment of the anti-peeping film are performed frequently, it is significantly inconvenient to the user. In addition, the price of the anti-peeping film is expensive and need to be preserved carefully if removing from the display device.